Yup, hemp was very widely used in the 18th century. It was used for a great many things, namely cordage, and some cloth., a lot of sails were hemp canvass. As a matter of fact the Hon. George Washington raised a great deal of it. He had discovered that tobacco farming was becoming slightly impracticable, as it deleted the land rapidly, and hemp for cordage, particularly for the rigging on the ships of the time, was allways needed, and hemp is much easier on the soil than tobacco. He was by no means alone in this assessment, either. All well documented.